Apparatus for evaporating and depositing a material



M y 22, 1956 K. H. STEIGERWALD 2,746,420

APPAIEATUS FOR EVAPORATING AND DEPOSITING A MATERIAL Filed Nov. 4, 1952 2 Sheets-Sheet 1 Fig. 1

y 22, 1956 K. H. STEIGERWALD 2,746,420

APPARATUS FOR EVAPORATING AND DEPOSITING A MATERIAL Filed Nov. 4, 1952 2 Sheets-Sheet 2 Fig.2

I a I I y 603 A 62} E 63 341' 56$ 57 5e W A? E "J 7 k\\\\\\\\\\\\\\ \\\\V\\\\\\\\\YI fn l/Lffyfafl; Km! 4 United States Patent APPARATUS FOR EVAPORATING AND DEPOSITING A MATERIAL Karl Heinz Steigerwald, Mosbach (Baden), Germany Application November 4, 1952,, Serial No. 318,580

Claims priority, application Germany November 5, 1951 32 Claims. (Cl. 118-8) The present invention relates to an apparatus for evaporating a material and depositing the evaporated material as a layer, and more particularly to an apparatus for producing metallic mirrors and/or protective layers.

It is an object of the present invention to obtain layers of the kind described which have a predetermined thickness.

It is another object of the present invention to control the velocity of evaporation.

It is a further object of the present invention to provide an apparatus which allows to carry out the evaporation and depositing of the material in several layers.

It is still another object of the present invention to provide an apparatus permitting to produce optical glasses having multiple layers with refractive indices changing stepwise or continuously.

It is a still further object of the present invention to provide an apparatus which allows to provide a plurality of objects in a continuous process with reflecting or protective layers.

An apparatus according to the present invention comprises in its broadest aspect means for directing the beam of electrically charged particles to a spot on the surface of the material so as to heat the spot and evaporate the material so as to form a cloud, means for adjusting the directed beam, means for controlling the adjusting means, and at least one member arranged outside of the beam of electrically charged particles and within the cloud of evaporated material so that the evaporated material is deposited from the cloud on the member as a. layer.

A preferred embodiment of the present invention comprises in combination an evacuated vessel having a first portion and a second portion, means arranged in the first portion of the evacuated vessel for emitting a beam of electrons, the emitting means including a glow cathode, a metal cylinder surrounding the glow cathode, and a funnel-shaped electrode arranged within the metal cylinder, means arranged in the second portion of the evacuated vessel and containing the material to be evaporated, means for directing the beam of electrons to a spot on the surface of the material, the directing means including an electron-optical image-forming device forming an image of the glow cathode on the spot so as to heat the spot and evaporate the material so as to form a cloud, means for adjusting the directed beam, light-sensitive means for controlling the adjusting means, a carrier arranged in the second portion of the evacuated vessel for holding at least one member so as to be arranged outside of the beam of electrons and within the cloud of evaporated material so that the evaporated material is deposited from the cloud on the member as a layer.

Another embodiment of the present invention comprises in combination, an evacuated vessel having walls, means arranged in the vessel for emitting a beam of electrons, means for directing the beam of electrons to a spot on the surface of the material so as to heat the spot and evaporate the material so as to form a cloud 2,746,420 Patented May 22, 1956 in the vessel, electromagnetic means for adjusting the directed beam, light-sensitive means for controlling the adjusting means, a window arranged in the wall of the evacuating vessel permitting the radiation from the spot to reach the controlling means, and at least one member arranged in the evacuated vessel outside of the beam of. electrons and Within the cloud of evaporated material so that the evaporated material is deposited from the cloud on the member as a layer.

A preferred embodiment of the present invention comprises in combination an evacuated vessel, a lock chamber arranged alongside the vessel, means for preventing and establishing a communication of the lock chamber with the vessel, an object carrier, means for transporting the object carrier from the lock chamber to the evacuated vessel and vice versa, means arranged in the evacuated vessel for emitting a beam of electrons, means for directing the beam of electrons to a spot on the surface of the material so as to heat the spot and evaporate the material so as to form a cloud forming a layer on the objects carried by the object carrier, means for adjusting the directing means, and means for controlling the adjusting means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the followingdescription of specific embodiments when read in connection with the accompanying drawings, in which Fig. 1 is a diagram of a first embodiment of the present invention; and

Fig. 2 is a modification of the embodiment shown in Fig. 1.

Referring now to the drawings, and first to Fig. 1, a base plate 17 supports a device for receiving the material to be evaporated which is formed by a metal cylinder 31 provided with a hollow 31 communicating with a boring in the upper end face 31" of the cylinder 31 through which the material to be evaporated extends. The material has the form of a pressed rod 18 consisting e. g.

of thorium oxide which is supported by a screw 21 screwed into the base plate 17 and being so adjusted that a short end 18 of the rod 18 projects beyond the cylinder 31.

A metal casing 11 termed hereinafter the second portion is supported by the base plate 17 and forms together with the base plate and an extension 33 an evacuated vessel. The base plate 17 forms one of the end walls of the second portion opposite to which is arranged the other end wall 11. In the evacuated vessel is arranged in a manner to be described more in detail hereinafter a carrier 14 carrying the members or objects 32 such as optical lenses on which a layer of the evaporated material has to be deposited. The vapor of the material is obtained by heating the end face 39 of the end 18' of the rod 18 which projects beyond the cylinder 31. A semispherical diaphragm 37 provided with suitable cutouts is arranged above the cylinder'31 so that the vapor forms beams such as 39 propagated in the desired directions.

In order to heat the end face 39 of the material 18 a beam of electrically charged particles such as electrons 4 is made to impinge on the end face 39. The beam of electrons is generated by a device more fully to be described hereinafter which is arranged in the tubular extension 33 termed hereinafter the first portion and consisting of metal, the extension 33 opening through an aperture in the end wall 11 into the second portion 11.

The tubular extension 33 is closed at the end 33. opposite to the second portion 11 in a high vacuum-tight manner and carries there a glow cathode 34 preferably the Wehnelt cylinder 1 a funne1shaped metal electrode 3G is arranged which is kept at the same potential as the cylinder 1. The funnel-shaped electrode 30 is with its larger edge 30' galvanically connected to the cylinder 1 and surrounds with the smaller edge 30" thereof the hairpin cathode 34 at the tip thereof. The tubular extension 33 and the parts carried by the same are mechanically adjustable relative to the casing 11 by means of a resilient intermediate tubing 49 and adjusting screws 50 by means of which the extension 33 and the parts thereof can be tilted in a certain way so that the electron beam 4 can be directed to the face 39 to be evaporated. The base plate 17 has an aperture 17' communicating with a tube 48 to which a high vacuum pump (not shown) is connected.

A knife 19 is arranged on top of the cylinder 31 and serves for cutting off the end 18' of the rod 18 projecting beyond the cylinder 31 in order to smoothen the end face of the rod 18 from time to time. The knife is driven by a driving device 20 which can be actuated from the outside of the evacuated vessel by means of the handle 35.

The casing 11 is provided with windows 22- and Ben the outside of which photoelectric cells 9 and are arranged, respectively. The photoelectric cell 10 receives the light beam from a light source such as an incandescent lamp 25 arranged within the evacuated vessel, after the light has traversed a glass disc 24 rotatable from the outside by means of the, knob 36. A diaphragm 37 is provided with a cutout letting pass a jet of vapor which impinges on the part of the glass disc 24 illuminated by the light source 25. In this way a layer of material is formed on the glass disc 24 the absorption of which is registered by the photoelectric cell 10 which is connected to an amplifier 8. Instead of the absorption of the deposited layer the diminution or increase of the reflection of the light could be measured by the photoelectric cell 10.

The photoelectric cell 9 arranged behind the window 22 is inclined and receives through a cutout of the diaphragm 37 light and/or heat radiation emitted by the intensely heated end face 39 which is in a state of melting. The thus generated measuring voltages or currents are also fed to the amplifier 8. In order to avoid that the measured values are falsified by any layers of material deposited on the window 22 a device is provided consisting of a reel 26 of transparent film which is wound on the reel 26' during the evaporation and the depositing of the material. The drive of the reels 26, 26' can be effected by a clockwork (not shown) arranged in the evacuated vessel or the transport of the transparent film can be effected stepwise of continously by hand.

The amplifier 8 is connected to an auxiliary device 6 generating the common control voltage of the Wehnelt electrode 1 and the funnel-shaped electrode 30. The amplifier 8 is also connected to a high voltage device 7 which is connected to the central electrode 27 of an electrostatic lens 3 arranged near the end of the extension 33 opposite to the end 33. Thus the amplifier 8 controls the potential of the electrodes 1 and 30 and of the central electrode 27. Also the time interval during which the electron beam 4 acts on the spot of evaporation can be controlled by means of the amplifier 8 and, if desired, the electron beam 4 can be automatically shut off from the spot of evaporation 39. This can be effected for instance by means of blocking or deflecting the electron beam 4 by electrical, magnetic or electron-optical means or by mechanical means (not shown), for instance by increasing the negative Wehnelt potential, cutting off the accelerating voltage or the heating current of the glow cathode, arranging a mechanical blocking flap, or shifting the reach of the electron beam 4.

The electrostatic lens 3 comprises furthermore two outer electrodes 28 and 29.

An auxiliary device 5 is provided for generating and.

if desired adjusting the heating current of the tungsten glowing cathode 30. It should be understood that the devices 5 to 8 shown as block diagrams are well known electronic devices comprising vacuum tubes, rectifiers, transformers and the like.

Between the glow cathode 34 and the lens 3 one or more diaphragms 2, which may be adjustable, if desired, are arranged the opening of which is so chosen that it cuts out of the electron beam 4 a sharply limited beam having the shape of the diaphragm opening. The opening of the diaphragm 2 may be circular, rectangular or of any other cross section. The electron beam 4 penetrates the lens 3 and an aperture 38 provided in the carrier 14 of the objects and impinges on the spot 39 of evaporation.

The electrostatic lens 3 can be replaced by an electromagnetic lens (not shown) the current of which is controlled by the amplifier 8 in a manner corresponding to the control of the potential of the central electrode 27.

The carrier 14 of the objects 32 consists of a partspherical cap at the lower side of which holders (not shown) for the objects or lenses 32 are arranged which are to be provided with deposits of material. The upper part of the object carrier 14 is provided with two guiding rails 40 which are so long that the object carrier 14 can be shifted without any difficulty along the guiding rails 15, 15', 15" and the gaps 15a thereof. The gaps 15a between the guiding rails 15, 15', 15" are provided in order to enable closing flaps 41 and 42 arranged between the casing 11 and left-hand and right-hand lock chambers 13 and 12 to move from the closing position into the opening position and vice versa. In the drawing the flap 41 connecting the casing 11 with the lock chamber 12 is shown in closed position whereas the flap 42 connecting the casing 11 with the lock chamber 13 is shown in open position. The lock chambers 12 and 13 are connected by flanges (not shown) to the chamber 11 and communicate therewith, respectively, through openings 12' and 13 which can be closed, respectively, by the flaps 41 and 42. The lock chambers 12, 13 contain, respectively, the guiding rails 15', 15" and have at the outer ends thereof closing doors 43 and 44, respectively. 45 and 46 are tubings connected, respectively, to the lock chambers 12 and 13 and serve for the connection with a high vacuum pump (not shown).

The operation of this device is as follows:

The lenses 32 are attached to the lens carrier 16 which is inserted into the right-hand lock chamber 12 by means of the door 43 which is opened for this purpose. The flap 41 is during this part of the operation in closed position as shown in the drawings. Then the door 43 is closed and the lock chamber 12 is evacuated by the high vacuum pump through the tube 45 so that it has the same high degree of vacuum which is maintained within the evacuated vessel composed of the chamber 11 and the extension 33. Then the flap 41 is opened and by means of a shifting device (not shown) to be actuated from the outside the object carrier 16 is shifted along the guiding rails 15' and 15 into the casing 11 from which previously the object carrier 14 was shifted into the lock chamber 13 which had been evacuated through the pipe 46, the door 44 and the flap 42 being closed. After the shifting of the object carrier 14 the flap 42 is closed so that the place of the object carrier on the guiding rail 15 in the casing 11 is empty and the object carrier 16 can be shifted into the evacuated vessel consisting of the casing 11 and the extension 33 after which the flap 41 is also closed in order to enable a new loading of the lock chamber 12. The carrier 14 carrying lenses on which material such as thorium oxide has been deposited and which is now in the lock chamber 13 is removed from the same through the door 44. This arrangement permits such as 14,and16.

the evacuated vessel consisting of the casing 11 and the extension 33 to be maintained under vacuum notwithstanding the introduction and. removal of object carriers The evaporation and depositing of the material shall now be described in detail under the assumption that a carrier denoted by 14 is in the evacuated vessel composed of the casing 11 and the extension 33, both the flaps 41 and 42 being closed. An electron beam 9 is emitted by the cathode 34 which passes through the diaphragm 2 and is limited in cross-section by the same. By means of the lens 3 a sharp electron image of the diaphragm 2 is formed at the place of the evaporating spot 39. By adjusting the focal length of the lens 3 a reduction of the sharpness of the image and thus a reduction of the current density at the evaporating spot 39 can be obtained which is equivalent to a reduction of temperature and thus to a slowing down of the evaporating and depositing process. The potential of the lens 3 can even be entirely cut off or the lens 3 may be entirely omitted so that the contours of the diaphragm 2 appear on the evaporating spot 39 according to the principles of casting shadows. If desired, also the diaphragm 2 can be omitted so that the form of the beam is determined by the remaining beam forming system. The control of the beam by means of the control electrodes 1 and 30 of the beam forming systemcauses a change of the total current and of the current density of the beam of charged particles and thus a change of the temperature generated at the evaporating spot 39 and an extension of the temperature intervals.

The measuring voltages or currents of the photoelectric cell 9 correspond to the light flux emitted by the evaporating spot 39 and thus to the power which is effective here. They give a direct measure of the intensity of the vapor jet emitted by the evaporating spot 39. In the amplifier 8 these measuring values are transformed into an alternating voltage signal having a frequency for instance of 20,000 cycles per second and an amplitude dependent on, or pro portional to, the current values supplied by the photoelectric cell 9. The alternating voltage is supplied by means of a high frequency insulating transformer to the auxiliary device 6 generating the Wehnelt control voltage and influencing by means of a suitable arrangement of interconnected rectifiers and controlling devices the control voltage generated by the auxiliary device 6 which controls directly the intensity of the electron beam. If, for instance, accidental thermal changes occur at the evaporating spot 39 by mechanical changes in the pressed rod 18, these are registered by the photoelectric cell 9. The control voltage for the beam forming system can be regulated via the amplifier 8 and the auxiliary device 6 so as to change the intensity or form of the beam of electrons in such manner that the temperature change of spot 39 is compensated so as to obtain a stabilization of the entire evaporating process. Similar effects may be caused by unforseen electrical charges at the spot 39. Furthermore, it is possible to adjust in this manner, for instance, the temperature or the magnitude of the heated surface according to a preset course.

The photoelectric cell registers the optical properties of the generated deposits and therefore, for instance, the thickness thereof. The signal supplied by the photoelectric cell It) acts via the amplifier 8 and the auxiliary devices 6 and 7 on the control voltages of the beam forming system and the lens 3. By means of particular adjusting members (not shown) arranged in the amplifier 8 it can be obtained, for instance, that the evaporating speed increases or decreases from a predetermined layer thick ness onwards.

In the embodiment shown in the drawings only one evaporating device is provided. If a plurality of evaporating devices are to be used preferably each evaporating device is provided with a corresponding controlling device.

The amplifier 8 may consist of two separate amplifiers containing for instance one or more high vacuum amplify ing tubes so that by one of the supervising devices (photoelectric cell 9) the input of one amplifier is controlled whereas the input of the other amplifier is controlled by the other supervising device (photoelectric cell 10). The outputs of the two amplifiers can be connected in such manner that the desired various controls are efiected in the manner described hereinabove.

The beam 4 is preferably an electron beam; however, it should be understood that instead of electrons other charged particles, for instance, ions can be used.

Furthermore, the invention consists in that in principle in manufacturing layers on optical glasses, particularly lenses the heating of the material to be evaporated is carried out by means of a beam of charged particles, particularly an electron beam, preferably with use of one or more devices described hereinabove.

Thus it is seen that the present invention consists in the heating of the material to be evaporated by means of a beam of charged particles in such a way that the geo metrical shape and/ or electrical properties of the beam are controllable or stabilizable by hand and/or automatically by means of mechanical and/or electrical or magnetical devices via light--and/or thermoelectrical supervising devices.

Before the evaporation proper is carried out it is often desirable to cleanse the spot to be evaporated. According to the present invention also to this purpose a beam of electrically charged particles and particularly the beam used for the evaporation can be used if necessary in connection with electron-optical (electrical or magnetic or electromagnetic) deviating devices or mechanical swivelling devices by means of which the covering of the entire spot to be cleansed can be efiected.

The determining factor of the course of the evaporating process is the temperature reached by the material to be evaporated and the magnitude and shape of the highly heated surface thereof. According to the present invention the evaporating process can be controlled or stabilized in a convenient manner by supervising by means of photoelectric or thermoelectric devices the light or heat radiation emitted by the highly heated material. The current or voltages obtained by the supervising devices can be used for controlling the beam of charged particles by hand or preferably automatically with insertion of suitable elec' trical and/or mechanical controlling members. In order to control the thickness of the deposited layer and to finish the evaporation in time when a predetermined thickness or shape of the layers has been reached it is preferable to check by means of photoelectric or thermoelectric devices the brightness or color of a light source as it appears through a transparent surface exposed to the vapor jet.

Under certain circumstances it is desirable to carry out the depositing of a multiple layer consisting of two or more layers of different materials. In this case the switchover to the succeeding evaporating process is elfected in dependency on the supervising device.

In particular cases it is desirable to obtain multiple refining layers on optical glasses with stepwise or continuous transitions of the refractive index. With this aim in view the process according to the present invention can be modified so that either several beams of charged particles are provided which can be directed arbitrarily to the ma terials to be evaporated and which are either simultaneously or alternatively switched on in the manner most suitable for the deposited layers, or the intensity of the beams can be adjusted in a predetermined ratio. Under circumstances electron beams can be additionally controlled so as to be intermittent at short periods so as to produce layers which are finely subdivided. Another possibility consists in directing one or more electron beams alternatively to ditferent materials or different surfaces of the same material by means of electrical or mechanical deflecting devices. In this manner it is possible under circumstances to carry out by means of a single electron evaporated.

,Care should be taken that parts of the beam forming system and; particularly the lens thereof are at a high potential against ground and that for the control under certain circumstances also high voltage disconnecting members or electrical and/or mechanical controlling devices can be arranged at a high potential against ground.

In order to avoid errors in the supervision of the evaporation or depositing, devices can be provided which intermittently or continuously clean the windows exposed to vapor jets. Instead of this, transparent protective members can be continuously transported in front of the windows to be protected so that they carry off the deposited layers, or before each charging the transparent members can be put in position in front of the measuring window together with the carrier carrying the objects or independently of the same.

In a similar manner as the objects to be provided with layers also the material to be evaporated may be continuously or intermittently transferred to the place of evaporation, for instance, by locking devices or from a magazine provided in the evacuated vessel. Correspondingly the material or the remainders thereof can be taken out of the vacuum or transported from the place of evaporation.

Preferably a light source and a corresponding window such as 47 are provided which are independent from the processes going on within the evacuated vessel in order to continuously control and observe the processes taking place Within the evacuated vessel.

The devices generating or deviating the electron beam can be arranged so that the electron beam strikes the spot of evaporation either from above through a suitable opening between the objects to be provided with a de posited layer as described hereinabove or sideways at an inclination to the objects. If several electron beams are employed the same can be arranged so as to be radially symmetrical with respect to the central axis of the space angle exposed to the vapor jets. In certain cases, however, asyinmetrical arrangements are preferable.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatuses for evaporating a material and depositing the evaporated material as a layer differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for producing metallic mirrors, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essentially characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

Figure 2 shows diagrammatically an arrangement in which a plurality of electron beams for simultaneous or selective operation is provided. In an evacuated vessel 52 corresponding to the casing 11 shown in Fig. l a plurality of electron beam sources 53, 54, 55 is arranged, the structure of which corresponds to the arrangement provided within the tubular extension 33 shown in Figure 1.

Furthermore it is preferable for carrying out more complicated evaporating processes to provide devices carrying a plurality of materials to be evaporated. Figure 2 shows as an example a hollow member 59 arranged on the base plate 100 of the chamber or evacuated vessel 52 which is provided with openings for accommodating three substances 56, 57 and 58 to be evaporated. It should be 8 understood that the device 59 corresponds to the device 31 shown in Fig. 1. Of course each of the substances 56, 57 and 58 is provided with a separate adjusting screw 102,

. 104 and 106, respectively.-

If a plurality of electron beams are provided as in Fig. 2, preferably controlling devices for the electron beams are arranged so that the electron beams can be switched on simultaneously or selectively. Furthermore means are provided for maintaining the ratio of the intensities of the different electron beams or for adjusting the same. Thus for instance, the controlling devices corresponding to the devices 5, 6, 7 and 8 shown in Fig. l and the supervising devices 9 and 10 are provided for each of the electron beam sources 53, 54 and 55 and the controlling devices are coupled with each other so that a predetermined functional relation between the intensities of the electron sources 53, 54 and 55 can be obtained by means of suitable selecting devices.

Furthermore the controlling devices are connected in such manner that for instance when a predetermined state of evaporation or a predetermined temperature of the material to be evaporated has been reached the electric and electron-optical values of the individual beam sources follow predetermined. functions of arbitrary order in dependency on the time. For instance when the material 56 has reached a predetermined temperature, the material 56 being heated by an electron beam emitted by the source 53, the material 57 is evaporated with an intensity increasing according to the square function.

A further feature of the invention consists in that a plurality of materials to be evaporated are arranged at a plurality of evaporating spots, respectively, so that they are struck by a plurality of stationary or movable electron beams or a single movable electron beam simultaneously and/or in a predetermined sequence.

In order to be able to shade parts or the entirety of the surfaces of the evaporating spots from the electron beam or beams mechanical shading flaps 60, 61 and 62 are provided and diagrammatically shown in Fig. 2. These flaps have, respectively, axes 63, 64, 65 which are extended in a vacuum tight manner beyond the casing 52 and are movable either by hand or by means of electro-mechanical servo-mechanisms (not shown).

Referring once more to Fig. 1, a vacuum measuring device is provided which automatically starts the evaporating process when the vacuum required for the evaporation has been reached. For instance, an arrangement shown as a block diagram 51 is shown in Fig. 1, consisting of a well known vacuum measuring device and being connected to the evacuated vessel by means of a connecting tube 67. The vacuum measuring device 51 includes a device which transmits at a predetermined pressure Within the evacuated vessel 11 a signal to the amplifier 8. In this way for instance the bias of the electrode 1 can be changed so that a blocking of the electron beam caused by a negative bias of the electrode 1 is rendered ineffective.

Furthermore it is desirable to use electron beams not only for carrying out the evaporating process but also for a preliminary cleaning or treating of the spots to be evaporated. Thus one or more electron beams are provided which serve for the cleaning of the surfaces of the objects to be evaporated. Under certain circumstances the arrangement can be made so that the electron beam or beams serving for the evaporation are simultaneously used for striking the surface to be cleaned, the beam or beams being deviated to the surfaces to be cleaned by means of deflecting devices. Figure 1 shows a holding device supporting a rod 71 consisting of ceramic material and serving as an insulator to which a beam generating system 72 is attached which is designed in the manner of a tele-focus cathode.

Furthermore the insulator 71 supports an electrostatic lens 73 the outer electrodes of which are at ground one another and are provided through the conductor systems 75, 76 with the required operating potentials. The conductors 75 and 76 are let out of the vacuum by means of a vacuum tight gasket 77 arranged in the base plate 17 and connect the electrodes with the means 78 required for controlling the same. The means 78 shown as a block diagram are connected to the amplifier 8 by means of the conductor 90.

In operation the electron beam generated by the telefccus cathodes 72 is focussed by means of the electrostatic lens 73 in any manner or is even de-focussed. The beam of electron rays is deviated by the deflecting plates 74 either subsequently or simultaneously to the surface of the objects 32 which are to be provided with a deposited layer. This process can be carried out before, during and after the evaporating process proper. The electrode controlling means 78 include means for giving to the electron beam 80 generated by the tele-focus cathode 72 a predetermined intensity preferably depending on the evaporating process proper.

What is claimed as new and desired to be secured by Letters Patent is:

1. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting said directed beam; means responsive to the temperature of said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

2. An apparatus for evaporating a material and de positing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the geometrical shape of said directed beam; means responsive to the temperature of said spot for controlling said adjusting means; and one means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

3. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means i for emitting a beam of electrically charged particles;

means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the focus of said directed beam; means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; and means responsive to the thickness of said layer for controlling said adjusting means.

4. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the current density of said directed beam; means responsive to the intensity of light emitted from said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporatedmaterial so that said evaporated material is deposited from said cloud on said member as a layer.

5. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the materialso as to form a cloud; electrical means for adjusting the focus of said directed beam; means responsive to the intensity of light emitted from said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

6. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directingsaid beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the current density of said directed beam; means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; and means responsive to the thickness of said layer for controlling said adjusting means.

7. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for deflecting said directed beam; heatsensitive means responsive to the temperature of said spot for controlling said deflecting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

8. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; electromagnetic means for adjusting the geometrical shape of said directed beam; means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; means responsive to the light emitted by said spot for controlling said electromagnetic means; means for adjusting the current density of said beam; and means responsive to the thickness of said layer for controlling said last named means.

9. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; electromagnetic means for adjusting the geometrical shape of said directed beam; light-sensitive means responsive to the light emitted by said spot for producing an electrical control current; electronic means including an amplifier and fresponsive-tosaid control current for controlling said adjusting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

10. An apparatus for evaporating a material and dcpositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; electromagnetic means for adjusting the geometrical shape of said directed beam; first light-sensitive means responsive to the radiation emitted by said spot heated by said directed beam of electrically charged particles, said light-sensitive beams producing an electrical control voltage for controlling said adjusting means; means for indicating said control voltage; means for positioning saidmember outside of said beam of electrically. charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; and second light-sensitive means for indicating the thickness of said layer.

11. An apparatus for evaporating a material and depositing the evaporated material as a layer on a, member it is desired to coat comprising, in combination, means for emitting a beam of electrons, said emitting means including a glow cathode, a metal cylinder surrounding said glow cathode, and a funnel-shaped electrode arranged Within said metal cylinder; means for directing said beam of electrons to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting said directed beam; means responsive to the intensity of light emitted from said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrons and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

12. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrons, said emitting means including a glow cathode, a metal cylinder surrounding said glow cathode, and a funnel-shaped electrode arranged within said metal cylinder; a diaphragm for limiting the cross section of said beam of electrons; means for directing said beam of electrons to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting said directed beam; means responsive to the intensity of light emitted by said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrons and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

13. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, means for emitting a beam of electrons, said emitting means including a glow cathode, a metal cylinder surrounding said glow cathode, and a funnel-shaped electrode arranged within said metal cylinder; a diaphragm for limitiug the cross section of said beam of electrons; means for directing said beam of electrons to a spot on the surface of the material, said directing means including an elec tron-optical image-forming device forming an image of said diaphragm on said spot so as to heat said spot and,

evaporate the material so as to form a cloud; means for adjusting said directed beam; means responsive to the member outside of said beam of electrons and within- 12 intensity of light emitted from said spot for controlling said adjusting means; and means for positioning said said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

14. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, an evacuated vessel having a wall portion; means for mechanically adjusting the position of said wall portion; means arranged in and mechanically connected to said wall portion for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting said directed beam; means responsive to the temperature of said spot for controlling said adjusting means; and means for positioning said member outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

15. An apparatus for evaporating a material and depositing the evaporated material as a layer comprising, in combniation, an evacuated vessel having a first portion and a second portion having two end walls arranged opposite to each other, said first portion opening into one of said end walls of said second portion; means arranged in said second portion of said evacuated vessel for emitting a beam of electrons, said emitting means including a glow cathode, a metal cylinder surrounding said glow cathode, and a funnel-shaped electrode arranged Within said metal cylinder; means arranged on the other of said end walls of said second portion of said evacuated vessel and containing the material to be evaporated; means for directing said beam of electrons to a spot on the surface of the material, said directing means including an electron-optical image-forming device forming an image of said glow cathode on said spot so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting said directed beam; light-sensitive means responsive to the intensity of light emitted by said spot for controlling said adjusting means? and a carrier arranged in said second portion of said evacuated vessel for holding at least one member outside of said beam of electrons and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

16. An apparatus for evaporating a material and depositing the evaporated material as a layer on an article it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; a pressed body consisting of the material to be evaporated; means for adjusting the position of said body; means for ,directing said beam of electrically charged particles to a spot on a surface of the body so as to heat said spot and evaporate the material of the body so as to form a cloud; means for adjusting said directed beam; means responsive to the intensity of light emitted by said spot for controlling said adjusting means; and means for positioning said article outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on at least one surface of said article as a layer.

17. An apparatus for evaporating a material and depositing the evaporated material as a layer on an article it is desired to coat comprising, in combination, means for emitting a beam of electrically charged particles; a pressed body consisting of the material to be evaporated; means for adjusting the position of said body; means for directing said beam of electrically charged particles to a spoton a surface of the body so as to heat said spot and evaporate the material of the body so as to form a cloud; means for removing a portion of said surface of 13 said body upon which said beam impinges; means for adjusting said directed beam; means responsive to the intensityof light emitted by said spot for controlling-said adjusting mean's;'and means for positioning said article for emitting a beam of electrically charged particles; a

pressed body consisting of the material to be evaporated; means for adjusting the position of said body; means for directing said beam of electrically charged particles to a spot on a surface of the body so as to heat said spot and evaporate the material of the body so as to form a cloud; means for mechanically smoothing said spot on which said beam impinges; means for adjusting said directed beam; means for controlling said adjusting means; and means for positioning said article outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer.

1 19. An apparatus for evaporating a material and depositing the evaporated material as a layer on a member it is desired to coat comprising, in combination, an evacuated vessel having walls; means arranged in said vessel for emitting a beam of electrons; means for directing said beam of electrons to a spot on the surface of the material so as to heat saidspot and evaporate the material so as to form a cloud in said vessel; electromagnetic means for adjusting said directed beam; light-sensitive means responsive to the intensity of light emitted from said spot for controlling said adjusting means; a window arranged in said wall of said evacuating vessel permitting the radiation from said spot to reach said controlling means; means arranged in said evacuated vessel in front of said window for preventing said window from being obscured by the vapors of the material; and means for positioning said member in said evacuated vessel outside of said beam of electrons and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said members as a layer.

20. An apparatus for evaporating a material and depositing the evaporated material as a layer comprising, in combination, an evacuated vessel; a lock chamber arranged alongside said vessel; means for preventing and establishing a communication of said lock chamber with said vessel; an object carrier; discontinuous transport rails for guiding said object carrier from said lock chamber to said evacuated vessel and vice versa; means arranged in said evacuated vessel for emitting a beam of electrons; means for directing said beam of electrons to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud forming a layer on the objects carried by said object carrier; means for adjusting said directing means; and means responsive to the intensity of light emitted from said spot for controlling said adjusting means.

21. An apparatus for evaporating a coating material and depositing it as a layer on an article it is desired to coat, comprising, in combination, a closed vessel having the coating material arranged therein; means coupled to said vessel for evacuating the same; means in said vessel adapted to emit a beam of electrically charged particles; means coupled to said last named means for directing said beam of electrically charged particles to a spot on the surface of said material so as to heat said spot and evaporate the material so as to form a cloud within said vessel; means for positioning within said vessel an article to be coated outside of saidbeam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is desposited from said cloud as a layer on a surface of said article; a vacuum measuring device coupled to said vessel for deriving a signal indicative of a given value of pressure within said vessel; and means coupled to said means adapted to emit a beam of electrically charged particles and responsiveto said signal for initiating the emission of said beam when the pressure Within said vessel reaches said given value.

22. An apparatus as set forth in claim 1 and further including second means for emitting a second beam of electrically charged particles; and means coupled to said second means for directing said second beam at said member it is desired to coat, said second beam serving to clean said member.

23. An apparatus as set forth in claim 22 and further including a control device coupled to said second means for focusing and de-focusing said second beam.

24. An apparatus for evaporating material and depositing it as a layer on a plurality of articles it is desired to coat comprising, in combination, means for emitting a first beam of electrically charged particles; means coupled to said last-named means for directing said first beam to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for positioning said plurality of articles outside of said first beam and within said cloud of evaporated material so that said evaporated material is deposited as a layer from said cloud on the surfaces of said plurality of articles; means for emitting a second beam of electrically charged particles; and means coupled to said last named means for directing said second beam at said surfaces it is desired to coat of said articles so as to clean said surfaces.

25. An apparatus for evaporating different substances and depositing them as layers on at least one article it is desired to coat comprising, in combination, means for emitting a plurality of beams of electrically charged particles; directing means coupled to said last named means for directing each of said beams to a different one of said substances and for focusing each beam as a spot on the surface of the substance so as to heat the substance and evaporate the same to form clouds; control means coupled to said means for emitting a plurality of beams for selectively controlling the emission of each beam of electrically charged particles and thereby controlling the speed of evaporation of said substances and the sequence of evaporation of said substances; and means for positioning said article outside of said beams and within the clouds of evaporated substances so that said substances may be deposited as layers on said article.

26. The apparatus as set forth in claim 25, further including means coupled to said control means and responsive to the intensities of light emitted from said substances as they are heated for actuating said control means.

27. An apparatus as set forth in claim 19 in which said means for preventing said window from being obscured by the vapors of the material comprises a strip of transparent material, and means for continuously moving said strip in front of said window so that any material deposited on said strip and tending to reduce the transparency thereof is continuously removed.

28. An apparatus for evaporating a substance and depositing the evaporated substance on an article it is desired to coat comprising, in combination, a source emitting a beam of electrically charged particles; means associated with said source for directing said beam to a spot on the surface of said substance so as to heat said spot and evaporate said substance so as to form a cloud; focusing means coupled to said last named means for controlling the focus of said beam; means coupled to said source for controlling the current density of said beam of electrically charged particles; deflecting means associated with said source for deflecting said beam of electrically charged particles; means for positioning said article outside of said beam and within said cloud so that said evaporated material may be de posited from said cloud as a layer on said article; and

control means coupled to said focusing means, said current density controlling means and said deflecting means for controlling their operation in response to the temperature of said spot and the depth of the layer deposited on said article.

29. An apparatus for evaporating a material and depositing the evaporated material as a layer on an article it is desired to coat comprising, in combination, a source emitting a beam of electrically charged particles; a pressed body consisting of the material to be evaporated; means for directing said beam of electrically charged particles to a spot on an end surface of said pressed body so as to heat said spot and evaporate the material so as to form a cloud; mechanical means positioned adjacent said end surface for removing a portion of said end surface so as to clean said surface; and means for positioning said article outside of said beam of electrically charged particles and within said cloud so that said evaporated material may be deposited from said cloud as a layer on said article.

30. An apparatus as set forth in claim 29, and further including mechanical means coupled to said bar for adjusting the position thereof relative to that of said beam.

31. An apparatus for evaporating a material and depositing the evaporated material as a layer on a memher it is desired to coat, comprising, in combination, means for emitting a beam of electrically charged particles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the focus of said directed beam; means for positioning said memher outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; and photosensitive means responsive to the thickness of said layer for controlling said adjusting means.

32. An apparatus for evaporating a material and depositing the evaporated material as a layer on a memher it is desired to, coat, comprising,.in combination, means for emitting a beam of'electrically charged par ticles; means for directing said beam of electrically charged particles to a spot on the surface of the material so as to heat said spot and evaporate the material so as to form a cloud; means for adjusting the focus of said directed beam; means for positioning said memher outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said member as a layer; a rotatable member positioned outside of said beam of electrically charged particles and within said cloud of evaporated material so that said evaporated material is deposited from said cloud on said rotatable member as a layer; a source of light disposed at one side of said rotatable member and adapted to transmit a beam of light through said layer deposited on said adjustable member; and photo-electric means disposed on the other side of said adjustable memher and responsive to the light transmitted through said layer deposited on said adjustable member for controlling said beam focus adjusting means.

' References Cited inthe fi le of this patent UNITED STATES PATENTS 2,157,478 Burkhardt et a1. May 9, 1939 2,206,509 Lederer July 2, 1940 2,301,456 Sabine Nov. 10, 1942 2,416,211 Osterberg et al. Feb. 18, 1947 2,426,016 Gustin et al. Aug. 19, 1947 2,428,868 Dimmick Oct. 14, 1947 2,463,180 Johnson Mar. 1, 1949 2,482,329 Dimmick Sept. 20,1949 2,516,908 Pottle Aug. 1, 1950 2,527,747 Lewis et al. Oct. 31, 1950 

1. AN APPARATUS FOR EVAPORATING A MATERIAL AND DEPOSITION THE EVAPORATED MATERIAL AS A LAYER ON A MEMBER IT IS DESIRED TO COAT COMPRISING, IN COMBINATION, MEANS FOR EMITTING A BEAM OF ELECTRICALLY CHARGED PARTICLES; MEANS FOR DIRECTING SAID BEAM OF ELECTRICALLY CHARGED PARTICLES TO A SPOT ON THE SURFACE OF THE MATERIAL SO AS TO HEAT SAID SPOT AND EVAPORATE THE MATERIAL SO AS TO FORM A CLOUD; MEANS FOR ADJUSTING SAID DIRECTED BEAM; MEANS RESPONSIVE TO THE TEMPERTURE OF SAID SPOT FOR CONTROLLING SAID ADJUSTING MEANS; AND MEANS FOR POSITIONING SAID MEMBER OUTSIDE OF SAID BEAM OF ELECTRICALLY CHARGED PARTICLES AND WITHIN SAID CLOUD OF EVAPORATED 